This disclosure is generally in the field of implantable medical devices and methods, including but not limited to drug delivery devices deployable within the urinary bladder.
Targeted delivery of drug to the local or regional tissue sites where the drug is needed continues to have room for improvement in a variety of diseases and conditions in humans and other mammals. This is particularly true for tissue sites that are not readily accessible to the physician, where controlled release of drug is needed over an extended period, where a sufficient amount of drug can be stored on-board an implantable device having a relatively small volume, and/or where device is deployable with minimally invasive systems and methods and provides minimal patient discomfort. The devices should be relatively simple in their construction and operation, to provide a robust device, reliable drug delivery, and cost effective device construction and assembly.
Implantable medical devices are described in patent application publications US 2010/0331770, US 2011/0152839, US 2012/0089122, and US 2012/0203203, which are incorporated herein by reference. Some of the devices described have one or more apertures, or orifices, through which drug is released from the device. It would be desirable to have alternative and/or improved devices and methods that use release orifices in the course of providing controlled release of drug in vivo. For example, it would be desirable to reduce or avoid the manufacturing cost associated with laser drilling microscale orifices in silicone tubing.
In some drug delivery devices that rely on diffusion, osmosis or a combination thereof, it may be difficult for the device to dispense the entire drug from the reservoir. This problem may be magnified where the drug, such as some anti-cancer drugs, are extremely expensive to produce. Accordingly, it would be desirable to make sure that all or most of the drug provided in the device actually is released from the device during a treatment period.